Lamp



Nov. 29, 1927.

F. A. HART LAMP &......... 2

` Filed Feb. l, 1926 or INVENTOR 7M cmi- B Y A TTORNE Y WrTNEESEEPatent' Nov. 29, 1927.

FREDERICK A. HART, OF NEW BRITAIN, CONNECTICUT.

LAMP.

Application tiled February 1, 1926. Serial No. 85,219.

My invention relates to lamps of the sort that stand on the floor andhave an 'adjustable extension arm which carries the light.

- My invention has for its principal object to provide certainimprovements-in lamps of the character mentioned.

To the above and other ends my invention consists incertain features ofconstruction and combinations andA arrangements of arts, all of whichwill be fully set forth erein and particularly pointed out in theclaims. y

In the accompanying drawings,

Fig. 1 is an elevation on a\reduced scale of a lamp embodying myinvention.

Fig. 21s a vertical central section through the upper part of the lampstand.

Fig. 3 is a perspective view of one of the friction disks.

Fig.' 4 is a plan view in section on the y line 4.4 of Fig. 2.

Fig. 5 is a top view of one ofthe joints.

Fig. 6 is a view similar to Fig. 4 but show-v ing a preferredconstruction.

Fig. 7 is a view of a washer used in the construction shown in Fig. 6.

The lamp shown in the drawing is designed to stand on the floor and tohold an incandescent electric light in a suitable po- 30 sition for theuse of a person-working at a desk. This particular lamp was moreespecially designedY for the use of persons operating typewriting andadding machines.

- The lam comprises a cast base 1 of sulficient breath and weight tokeep the lamp from being easily turned over, an upright or standard 2,consistin of a piece of rather light tubing, prefera ly steel, insertedin a suitable hole in the base 1 and suitably secured in position there,as forexample, by a set screw 3. Near its upward end the vtube 2 has twodiametrically opposite holes 5 made therein, these holes bein made withstraight up and down sides as s own in Fig. 2. An extension arm 6 passesthrough these two holes 5 and has -a plece 7 pivotedl thereto on a bolt8. This nipple is threaded as shown `at 9 and :hasa lamp socket 10screwed on to it in the usual way, and attached to said socket there isshown in the drawing a shade and reflector 11. v Said socket 10 andreiector 11 may be of any ordinary and suit'- able sort. l

The arm 6 may consist of a piece of tubing of rectangular cross section,but I find it cheaper and just as good to employ instead a channel barof the form shown in Fig. 2, made by making two longitudinalright-angular bends -in a strip of sheet metal, the open side beingdown.

The joint between the arms 6 and standard 2 is of novel and advantageousconstruction. It comprises a bolt' 12, inserted through holes pierced inthe standard 2 and through the side walls of the arm 6, a nut 13 screwedon to the end of .said bolt and two friction disks 14, each having ahole 15 through which the bolt passes. These disks which lie fiatagainst the sides of the arm 6, communicate the pressure of the nutthrough the standard 2 to said arm so as to furnish the frictiondesirable for holding the arm in any position to which it may be movedwhile permitting it to be readily adjusted by hand up and down. It isdesirable to make the standard 2 of rather light tubing and it was foundthat if plane disks 14 were employed the metal of the tube 2 would bespread by the pressure of the head of the bolt and the nut 13 and it wasnot practicable to get the desired degree of friction without distortingthe tube. For that and other reasons I have made the disks 14 withshoulders, arranged to take the lateral pressure of the edges of thestandard bounding the perforations 5 to prevent the spreading of thetube under the pressure of the bolt. Theseishoulders can be produced byproviding up'and down ribs on the disks 14 but I find it more convenientto cut in the outer surface of each disk two grooves 16 as shown inFigs. 3 and 4, these grooves being so spaced that the edges of the holes5 in the tube 2 just it into them. The outer walls of the groovesfurnish the necessary shoulders to prevent the spreading of the tube aswill be readily understood from an ins ection of Fig. 4. By this means arather lig t steel tube isstiflened to such an extent as to furnish anentirely satisfactory degree of friction. to maintaln the .arm 6 inwhatever position the user moves itl to.

In addition to stiifening the tube 2, the grooves 16 revent the disks 14from turning when t e arm 6 is swung up or down. TheV rubbing istherefore confined to the inner surfaces of the said disks and to thatpart of the outer surface of the arm 6 which 1s enclosed or embraced bythe said disks.

" The exterior surface of the lam may therefore be finished in anydesire ornamental wayl and no visible part of the finish willbe havingon its outer end screw threads to lit the ordinary lamp socket 10 and atits other end, bifurcated as shown so "as to form two cheeks which maybe drawn by the nut 19 on said bolt into frictional engagement with thefiat sides of the arm 6. his piece 7 is of course provided with a holethrough it for the cord 20, said cord passing out of the socket 10 throuh the piece 7 and into the upper part of t e arm 6 above the bolt 8.

The cord also asses above and back of the bolt 12, down t rough theupright standard 2, and out near the base of said standard through asuitable insulating washer 21. The tension on the cord will besuiiicient to prevent it from saggin down in the arm 6 to a pointwhereit wi be Visible.

The upper end of standard 2 may be finished in any suitable way. In thepresent instance a turned wooden plug or stopper 22 is inserted with afairly good fit in the upper end of the tube. This plug or end piece hasa saw-cut 23, indicated by dotted llines in Fig. 2, extendingdiametrically across it from the bottom of the plug up to about thelevel of the top of the tube. An axial counter-bore 24 from the top ofthe plug extends down deep enough to intersect the upper part of theslot 23, and a tapered wood screw 25 is screwed through 'the plug asshown. This screw has the effect of a' wedge to tighten the plug in thetube 2, this action being permitted by the saw-cut 23 without splittingthe plug.

While my lamp 1s described primarily as a iioor lamp, it will of coursebe understood that the standard tube-may, if desired, be shortened andthe lamp adapted to stand on some higher .support than the floor.

In Figs. 6 and 7 I have shown the same construction as in the otherfigures and as above'described, but have added two washers 26 on thebolt 12, one of said washers bein placed between the head of said boltan the tube 2, and the other between the nut 13 and said tube. These maybe round sheet metal Washers bent into cylindrical or arched form,but'with a radius of curvature a little less than that of the tube 2.This a pears in Fig. 6 where the parts are shown before the nut 13 .istightened, and it will be seen that two opposite edges of each washercontact with the tube, but the middle part of the washer stands Aalittle away from the tube. When the nut'is tightened, the washer issprung by the pressure into about the same radius of curvature as thetube, which it embraces closely. These washers greatly stiffen thearched portions of the standard against the pressure of the bolt andenable me to employ a lighter tubing for the standard 2 than 1spracticable without them, the washers enabling the thin tubing towithstand the necessary pressure without undue distortion. By usingthese washers I have been able to make a satisfactory standard 2 ofwelded steel tubing of a thickness of only about twenty-live thousandthsof an inch, and which tubing would be crushed inby the bolt 12\ and nut13I if used without the washers.

Various changes may be made, in the details of construction andarrangements without departing from my invention.

What I claim as new and desire to secure by Letters Patent, is:

1. In a lamp, the combination of a thin tubular standard perforated on oposite sides, the metal surrounding lthe e ges 0f said perforationsbeing yieldable, a lightsupporting arm passing through saidperforations, friction disks in said perforations,

each of said disks being provided. with shoulders registering with theside edges of said perforatious to take the lateral or spreadingpressure of said edges and prevent crushing or distortion of saidtubular standard, and means for applying transverse pressure to saidstandard and through it to said friction disks andby the latter to thelight-supporting arm. l

2. In a lamp, the combination of a thin tubular standard having oppositeperforations, the metal surrounding the edges of said perforations beingyieldable, an arm eX- tending through said perforations, friction disksin said perforations and between which said arm is mounted, said diskshaving shoulders registering lwith the side edges of said perforationsto take the lateral or spreading pressure of said edges and preventcrushin or distortion of said tubular standard, an a bolt extendingthrough said standard, said disks and said arm and serving both as apivot for said arm and as means for applying pressure to producefriction between said arm and said disks. e

3. In a lamp, the combination of a thin tubular standard havinglongitudinal perforations on opiposite sides thereof, the metalsurrounding t e edges of said perforations being yieldable, an armpassing through said perforations, friction disks in said perfora- 125 1tions and pressing against said arm, each of said dis s being grooved,and the,v edges boundlng said perforations l ing in the l grooved partsof each disk so tat the walls of said grooves may` take the lateralA orspreading pressure of the edges bounding said perforations and preventcrushing or distortion of said tubular standard, and a pivot extendingthrough. said standard, said disks and said arm and serving to applypressure to produce friction between said disks and said arm.

\4. In a lamp, the combination of a thin tubular standard having twooppositely disposed perforations in its walls, said perforations havingstraight sides extending longitudinally of said standard and the metalof the standard through which said perforations are made beingyieldable, two friction disks in said perforations and each made withtwo grooves to receive the straight edges of said perforations andtoprevent crushing or distortion of said tubular standard, an armbetween said disks and a pivot bolt for said arm arranged also to putpressure on said standard and disks to frictionally restrain said arm.

5. In a lamp, the combination of a thin tubular standard, an arm tosupport an electric light, said standard having oppositely disposedperforations through which said arm passes, the metal surrounding theedges of said perforations being yieldable, friction disks in saidperforations and on opposite sides of said arm, said disks beingprovided with shoulders registering with the side edges of saidperfor-ations to take the lateral or spreading pressure of said edgesand prevent crushing or distortion of said tubular standard, a pivotbolt passing through said standard, disks and arm and supplying thepressure to produce the necessary friction, and a cord of insulated wirepassing through said standard over said pivot bolt and along said arm tosupply current to said lamp.

6. In a lamp, the combination of a thin tubular standard having oppositeperforations, the metal surrounding the edges of said perforations beingyieldable, an arm extending through said perforations, friction disks insaid perforations and between which said arm is mounted, said diskshaving shoulders registering with the side edges of sald perforations totake thenlateral or spreading pressure of said edges and preventcrushing or distortion of said tubular standard, a. bolt extendingthrough said standard, said disks and said arm and serving both as apivot for said arm and as means for applying pressure to producefriction between said arm and said disks, and washers for said boltarched to embrace said standard.

7. In a lamp, the combination ot' a thin tubular standard havingopposite perforations, the metal surrounding the edges of saidperforations being yieldable, an arm extending through saidperforations, friction disks in said perforations and between which saidarm is mounted, said disks having shoulders registering with the sideedges of said perforations to take the lateral or spreading pressure ofsaid edges and to prevent crushing or distortion of said tubularstandard, a bolt extending through said standard, said disks and saidarm' and serving both as a pivot for said arm and as means for applyingpressure to produce friction between said arm and said disks, and sheetmetal washers for said bolt each of said washers made in the shape of anarch having a radius of curvature less than that of said standard andsprung by the pressure of said bolt into substantial conformity to thecurvature of said standard.

8. In a lamp, the combination of a thin tubular standard havingoppositeiy disposed perforations, the metal surrounding the edges ofsaid perforations being yieldable, friction disks in said perforations,a lightsupporting arm extending through said perforations between saiddisks, said arm consisting of a channel shaped flat bar made by forminga strip of sheet metal with an upper wall and two vertical walls to formHat surfaces to be embraced between said disks, a pvot bolt for said armacting also to put the necessary frictional pressure on said disks,means on said disks to prevent spreading of said standard under suchpressure, and a cord running through said standard and through said Hatlight-supporting arm to the electric light socket which is supported bysaid arm.

Signed at the borough of Manhattan, city of New York, in the county ofNew York and State of New York, this 28th day of January, A. D. 1926.

FREDERICK A. HART.

